Cultivating apparatus of the type described typically utilize a series of tines that are reciprocated into and out of the soil at predetermined intervals as the apparatus is advanced along the ground. Such apparatus may either be self-propelled or hand-drawn and a suitable source of motive power, such as, an internal combustion engine or electric motor is employed to reciprocate the tines through a power transmission drive. For example, U.S. Pat. No. 2,991,838 to Lane, No. 4,049,059 to Weibling and No. 4,305,470 to Anderson disclose hand-drawn tilling devices utilizing a power drill at one end of a handle for advancing the apparatus and which transmits power through an elongated shaft in the handle into a power transmission system, such as, a V-belt drive. U.S. Pat. No. 3,199,235 to Stacy is directed more to a hand-held snow blower which is supported on a skid for advancement over a surface to be cleared of snow.
U.S. Pat. No. 2,056,337 to Archibald discloses a tilling apparatus having a plurality of tines that are arranged in pairs and reciprocated by a crankshaft through openings in a bar into and out of the soil. The motion of the tines is not purely reciprocal but instead is in a generally ovate path whereby the successive advancement of the tines into the soil will result in propelling the device while at the same time loosening the soil. Other representative patents in this field are those to Reuben No. 3,921,373 and Classen No. 4,662,456.
A number of problems and drawbacks in the prior art can be overcome by devising a soil tiller which has a plurality of reciprocating tines mounted at the free ends of crank arms for sequential, vertically reciprocal motion in response to rotation of a crank. The driving force of the tines is adjustable to conform to the condition of the soil and the entire mechanism can be carried on a skid which is driven behind an operator so that the operator can adjustably control the attitude of the skid and angle of approach of the tines into the soil.